1. Field of the Invention
The present invention relates to the field of display, and in particular to a transparent liquid crystal display.
2. The Related Arts
As the technology rapidly progresses and various new technologies emerge, the transparent display technology is gaining much attention due to the characteristics and unique application of the transparent display panel.
The transparent display panel refers to a display which is transparent so that the viewer can both see the images displayed by the display and the actual background behind the display. The transparent display has many applications, such as, window display for building or vehicles. Other than those large-area applications, the transparent display is also applicable to handheld devices, such as, viewing a map while also viewing the view behind the display.
The majority of current display market is estimated to be replaced by the transparent displays, for example, in building, advertisements, and public information applications. The transparent displays are categorized as head-up display (HUD), transparent liquid crystal display (LCD) and the transparent organic electroluminescent display. In these transparent displays, the HUD is implemented with image projection, while transparent LCD and the transparent organic electroluminescent display meet the true definition of transparent displays.
In known technology, the transparent LCD often comprises an active area (comprising red, green and blue sub-pixels) and a transparent area (comprising no red, green and blue sub-pixels and being transmittable to external light); wherein the active area provides the images for the viewer while the transparency state of the transparent area allows the viewer to see the view behind through the display. Generally, the active area and the transparent area of the transparent LCD are controlled by independent thin film transistors (TFT). When the transparent area is controlled by separate TFT, at least four sets of TFTs controlling signal outputs for the entire pixel respectively control the red sub-pixel, green sub-pixel, blue sub-pixel, and transparent area. When the transparent area is designed to be located next to the red, green and blue sub-pixels, there are as many as six sets of TFTs controlling signal outputs to respectively control the red, green and blue sub-pixels, as well as the transparent areas next to the red, green and blue sub-pixels. The increase in the number of TFTs in the LCD will lead to the reduction in aperture ratio. Also, more TFTs imply more signal outputs, which leads to a complex control system for transparent LCD.